Allowed range for the upper limit for cloud size distribution, r₂, is shown as a function of M_BH (black lines) as derived in Eq. ( 23) for the cases w = 2.0, z = 2.00, and {g_ex = 3.0, g_in = 0.1}. The red line shows the lower limiting condition on r₂, again as a function of M_BH, holding for sources in whose light curves we detected reliable X-ray eclipses and defined by Eq. (26). Green points show the values of r₂ directly computed according to the procedure described in Sect. 5.1 for the sources of Table 1. See the text for details.